JP6294646B2 - Turbo compound system controller - Google Patents

Description

  The present invention relates to a control device for an engine turbo compound system, and more particularly, to a control device for a turbo compound system including a generator (electric turbo compound) that is rotated using exhaust gas energy.

  A turbo compound is a device that increases axle driving force, and rotates the turbine with engine exhaust and transmits the output to the crankshaft through gears, joints, etc., or rotates the generator to generate electricity. What is extracted and used as energy is known.

  This electric turbo compound is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2008-175126), and an outline thereof will be described based on FIG. 9. A turbocharger 01 including a turbine 01a and a compressor 01b is described. An energy recovery unit 010 that recovers energy by introducing a part or all of exhaust gas exhausted from the turbine 01a, a valve 07 that can freely adjust the ratio of exhaust gas introduced into the energy recovery unit 010, and the valve 07 are predetermined. And a valve controller 08 that controls opening and closing based on the control pattern.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-190145) discloses that in FIG. 2 of the document, an electric compressor 3 that is rotationally driven by an electric motor 3m to compress air and supply compressed air to the internal combustion engine 7; A turbine generator 2 that generates power by driving a generator 2g with a turbine 2t that is driven by exhaust gas from the internal combustion engine 7, and stores electricity that is generated by the turbine generator 2 and supplies electricity to the electric compressor 3. A configuration comprising means 12 is disclosed.

  Further, in Patent Document 3 (Japanese Patent Laid-Open No. 6-323158), in the first half of the exhaust stroke in which the combustion gas has a sufficient flow rate, exhaust gas is sent to the turbocharger through the first exhaust port, and the turbocharger is driven by exhaust gas energy. In the second half of the exhaust stroke when the energy was recovered and the combustion gas flow rate decreased, exhaust gas was sent to the energy recovery device by bypassing the turbocharger through the second port, and the back pressure at the turbine inlet of the energy recovery device decreased. It is disclosed that the energy of the exhaust gas is recovered and the engine output is increased.

JP 2008-175126 A JP 2010-190145 A JP-A-6-323158

Electric turbo compound (electrically assisted turbo power regeneration mode or turbine generator with a motor generator on the same axis as the turbocharger's turbine / compressor) rotates the turbine with compressor load torque or torque that overcomes motor regeneration torque It is necessary, and some pressure is required for engine exhaust gas. For this reason, the exhaust energy recovery by the electric turbo compound has a problem that the back pressure of the engine increases, the pumping loss increases, and the fuel consumption deteriorates.
Therefore, although the exhaust energy is recovered by the turbo compound, the effect of the turbo compound is reduced because it has a relationship that is offset by the deterioration in fuel consumption caused by the pumping loss due to the increase in back pressure.

  As described above, Patent Documents 1 and 2 disclose that exhaust gas energy is converted into electric energy and recovered, but a trade-off relationship with an increase in pumping loss of the engine accompanying an increase in back pressure. It does not describe the output control of the generator that takes into account the contradictory relationship.

  In Patent Document 3, as described above, the exhaust gas exhaust ports are used separately in the first half and the second half of the exhaust stroke, and even when the back pressure at the turbine inlet is reduced, exhaust energy is recovered and the engine output is reduced. Although it has been shown to increase, it is necessary to form two exhaust ports, which leads to an increase in the size of the device, and a trade-off relationship between an increase in pumping loss of the engine and the amount of energy recovered by the turbine generator It does not describe the generator output control that takes into account the contradictory relationship.

  Accordingly, the present invention has been made in view of such a problem, and a trade-off relationship between a deterioration in fuel consumption due to an increase in pumping loss due to an increase in engine back pressure and a fuel consumption improvement due to recovery of exhaust energy by turbo compound (a trade-off relationship). ) Is taken into consideration, and the purpose is to enable the fuel consumption reduction operation of the engine by performing the back pressure control and the output control of the generator.

  The present invention has been made in order to solve such problems, and is a turbocharger that supercharges intake air to the engine, a turbine generator that is rotated by exhaust gas from the engine, and a power generation amount of the turbine generator. Power generation amount control means for controlling, back pressure control means for controlling exhaust gas back pressure introduced into the exhaust turbine by bypassing or restricting the exhaust pressure, and setting the power generation amount of the turbine generator to a low fuel consumption mode An engine based on the relationship between the power generation mode setting means, the increase in pumping loss caused by an increase in back pressure for rotating the turbine generator and the amount of exhaust gas energy recovered by the turbine generator in the low fuel consumption mode And a turbo controller that controls the power generation amount control means and the back pressure control means so as to maintain low fuel consumption operation. Characterized in that was.

  According to this invention, the turbo controller is based on the relationship between the increase in pumping loss caused by the increase in back pressure for rotating the turbine generator and the amount of exhaust gas energy recovered by the turbine generator in the low fuel consumption mode. Control the power generation amount control means and the back pressure control means so that at least the amount of exhaust gas energy recovered by the turbine generator exceeds the fuel consumption deterioration due to the increase in pumping loss. By doing so, it becomes possible to reduce the fuel consumption of the engine.

  In the present invention, it is preferable that the power generation mode setting means has a regenerative maximum mode, a no regenerative mode, and the low fuel consumption mode, and the regenerative maximum mode does not limit the generated power of the turbine generator. When the regenerative operation is performed at the maximum capacity, the non-regeneration mode is a mode in which power generation of the turbine generator is stopped, and the low fuel consumption mode is neither the maximum regeneration mode nor the no regeneration mode is set. It is good to set to.

  According to this configuration, since the turbine generator performs power generation control according to the set operation mode, the storage state of the battery storing the power from the turbine generator, the in-vehicle power load state of the vehicle, the engine The power generation amount can be controlled according to the power generation state of the alternator driven by the crankshaft.

  In the present invention, it is preferable that the turbo controller includes a control calculation unit and a sensor signal input unit that are independent from the engine controller that controls the operation of the engine.

  As described above, the turbo controller (turbo ECU) is configured to include a control calculation unit and a sensor signal input unit that are independent from the engine controller (engine ECU) that controls the operation of the engine. For example, when a sensor signal is transferred to the turbo controller side via the engine controller by CAN (Controller Area Network) communication, or calculation processing is performed on the turbo controller side using the calculation result on the engine controller side In some cases, depending on the data transfer cycle from the engine controller side, there may be a delay in the control calculation on the turbo controller side, but by having an original control calculation unit and sensor signal input unit, Can solve the delay, engine Fuel consumption reduction control that follows changes in load becomes possible.

  Furthermore, since the turbo controller has a sensor signal input unit that is independent of the engine controller, it can input a signal that uniquely detects the turbine speed and the outlet pressure of the compressor accurately (without delay), leading to compressor surging. Therefore, it is possible to prevent the surge speed and the surging from surging rather than obtaining it through communication with the engine controller.

  In the present invention, it is preferable that the turbo controller has a back pressure power generation amount map in which a relationship with a power generation amount of the turbine generator capable of maintaining low fuel consumption with respect to the back pressure is set in advance. The power generation amount control means and the back pressure control means may be controlled based on the power generation amount map.

  As described above, the power generation amount control means and the back pressure control means are controlled using the back pressure power generation amount map in which the relationship between the back pressure and the power generation amount capable of maintaining the preset low fuel consumption operation is set. The power generation amount of the turbine generator can be controlled so as to exceed the fuel consumption deterioration due to the loss.

  Preferably, in the present invention, the turbocharger comprises an exhaust turbocharger, and a power generation turbine of the turbine generator is disposed on the exhaust downstream side of the exhaust turbocharger, and exhaust gas to the exhaust turbine of the exhaust turbocharger is disposed. It is preferable that a first bypass control valve for bypassing is provided, the back pressure control means is configured by the first bypass control valve, and the power generation amount control means is configured by a converter connected to the turbine generator.

  In this way, in the turbo compound system in which the power generation turbine of the turbine generator is arranged on the exhaust downstream side of the exhaust turbine of the exhaust turbocharger, the first bypass control valve for bypassing the exhaust to the exhaust turbine of the exhaust turbocharger is installed. Thus, the back pressure control means is configured by the first bypass control valve, and the power generation amount control means is configured by controlling the power generation amount by a converter connected to the turbine generator. Can be controlled.

  Preferably, in the present invention, the turbocharger comprises an exhaust turbocharger, and a power generation turbine of the turbine generator is disposed downstream of the exhaust turbocharger, and an exhaust gas flow flowing into the moving blades of the exhaust turbine It is preferable that a variable nozzle mechanism for reducing the pressure is provided, the back pressure control means is configured by the variable nozzle mechanism, and the power generation amount control means is configured by a converter connected to the turbine generator.

  In this way, in the turbo compound system in which the power generation turbine of the turbine generator is arranged on the exhaust downstream side of the exhaust turbine of the exhaust turbocharger, the variable nozzle mechanism that restricts the exhaust gas flow flowing into the rotor blades of the exhaust turbine of the exhaust turbocharger The back pressure control means is configured by restricting the exhaust gas flow by the variable nozzle mechanism, and the power generation amount control means is configured by controlling the power generation amount by the converter connected to the turbine generator. Pressure and power generation can be controlled.

  In the present invention, it is preferable that an electric compressor is disposed on the upstream side or the downstream side of the supply airflow of the compressor of the exhaust turbocharger.

  As described above, by providing the electric compressor, it is possible to control only the supercharging pressure without affecting the fluctuation of the back pressure. Therefore, the control of the supercharging pressure and the control of the back pressure become easy, and the control with high accuracy is possible. It becomes possible.

  In the present invention, it is preferable that the turbocharger comprises an electric compressor, and includes a second bypass control valve that bypasses exhaust gas to the power generation turbine of the turbine generator rotated by exhaust gas from the engine. The back pressure control means may be configured by a control valve, and the power generation amount control means may be configured by a converter connected to the turbine generator.

  In this way, in the turbo compound system in which the electric compressor and the turbine generator are disposed on the intake passage side and the exhaust passage side, respectively, by the second bypass control valve that bypasses the exhaust gas to the power generation turbine of the turbine generator. Since the back pressure control means is configured and the power generation amount control means is configured by a converter connected to the turbine generator, the back pressure and the power generation amount can be controlled with a simple configuration.

  According to the present invention, the back pressure is controlled in consideration of the trade-off relationship (a trade-off relationship) between the deterioration in fuel consumption due to an increase in pumping loss due to an increase in the back pressure of the engine and the improvement in fuel consumption due to the recovery of exhaust energy by the turbo compound. In addition, the engine output can be controlled to reduce the fuel consumption of the engine.

It is a whole block diagram which shows 1st Embodiment concerning the control apparatus of the turbo compound system of this invention. It is explanatory drawing which shows the exchange of the signal between engine ECU and turbo ECU. FIG. 3 is a detailed explanatory diagram of a main part on the engine ECU side in FIG. 2. FIG. 4 is a detailed explanatory diagram of a main part on a turbo ECU side in FIG. 3. It is a detailed explanatory view of the back pressure power generation amount map in FIG. It is a whole block diagram of a turbo compound system which shows 2nd Embodiment. It is a whole block diagram of a turbo compound system which shows 3rd Embodiment. It is a whole block diagram of a turbo compound system which shows 4th Embodiment. It is explanatory drawing of a prior art.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. It should be noted that the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely descriptions. It is just an example.

(First embodiment)
FIG. 1 shows a control apparatus for a turbo compound system according to a first embodiment of the present invention. This turbo compound system 1 is an exhaust turbocharger driven by exhaust energy as a turbocharger driven by exhaust gas energy of an engine 3. 5 and a turbine generator (electric turbo compound) 7 that is rotated using exhaust gas energy downstream of the exhaust gas flow.

  The exhaust turbocharger 5 is driven to rotate by the rotational force of the exhaust turbine 5a driven by exhaust gas from the engine 3 and the exhaust turbine 5a compresses the intake air and passes the compressed air through the intake passage 4 to the engine 3. And a compressor 5b to be supplied.

  The turbine generator 7 is provided with a generator 9 connected to a power generation turbine 7a driven by exhaust gas. A converter 11 is connected to the generator 9. An alternator is used as the generator 9, and the alternator is converted into DC power by a converter 11 so as to charge the battery 13 of the storage means. The battery 13 also serves as a power source for driving auxiliary machines 15 in the vehicle, for example. In addition, although the alternating current generator was demonstrated as a generator, although a direct current generator may be sufficient, the electric power generation amount should just be controllable with the turbo controller (turbo ECU) 17 mentioned later.

  An exhaust passage 19 connected from the engine 3 to the exhaust turbine 5a of the exhaust turbocharger 5 is branched in the middle, and a first bypass passage 21 is formed to bypass the exhaust turbine 5a and the power generation turbine 7a and exhaust the exhaust gas to the downstream exhaust passage. The first bypass passage 21 is provided with a first waste gate valve 23.

  The exhaust passage 19 connecting the exhaust turbine 5a and the power generation turbine 7a is branched in the middle to form a second bypass passage 25. A second wastegate valve 27 is provided in the second bypass passage 25 and bypasses the power generation turbine 7a and communicates with the downstream exhaust passage.

The engine 3 is a diesel engine or a gasoline engine used for automobiles, ships, stationary engines, and the like. The amount of compressed air and fuel supplied to the engine 3 is controlled according to the operating conditions, and this control is controlled by an engine controller (engine ECU) 29. The engine ECU 29 is composed of a control device different from the turbo ECU 17.
An outline of signal exchange between the engine ECU 29 and the turbo ECU 17 is shown in FIG.

In FIG. 2, the engine ECU 29 receives an engine speed signal, an accelerator opening signal, an air-fuel ratio (oxygen concentration) signal, a knock sensor signal, and sensor signals such as catalyst temperature and exhaust temperature related to catalyst information.
Based on these input signals, control such as target boost pressure calculation, air-fuel ratio control, fuel injection amount control, ignition timing control, and catalyst control is performed.
Then, information on the state quantity such as the engine speed and the fuel quantity is transmitted from the engine ECU 29 to the turbo ECU 17 through a communication line at a predetermined communication cycle.

Further, the engine ECU 29 determines the power generation mode of the turbine generator 7, and transmits the power generation mode command of the determination result to the turbo ECU 17 at a predetermined communication cycle.
The turbo ECU 17 receives the power generation mode command by the power generation mode setting means 31 of the turbo ECU 17 and controls the output of the turbine generator 7 so that the power generation output according to the power generation mode set by the power generation mode setting means 31 is obtained. To do.
Further, various signals from the exhaust turbocharger 5 side, for example, a pressure sensor 33 that detects the discharge pressure of the compressor 5b, a rotation speed sensor 35 that detects the rotation speed of the exhaust turbine 5a, and a back pressure that detects the back pressure after the exhaust turbine. Sensor signals are read from the pressure sensor 37 and the exhaust temperature sensor 38 for detecting exhaust temperature, and a margin is secured so that surging and over-rotation of the compressor 5b of the exhaust turbocharger 5 and excessive temperature rise of the exhaust temperature do not occur. The turbo ECU 17 performs the operation or the operation along the target supercharging pressure. The opening degree control of the first wastegate valve 23 is performed for these controls.

Determination of the power generation mode of the turbine generator 7 on the engine ECU 29 side will be described with reference to FIG.
Based on the engine speed and the accelerator (engine load) as shown in FIG. 3, a target boost pressure suitable for the operating state is calculated using a preset target boost pressure map 39. The calculation result is output as it is to the turbo ECU 17 as a target value and also input to the power generation mode determination means 41.

The power generation mode determination means 41 determines three modes: the maximum regeneration mode, the low fuel consumption mode, and the no regeneration mode.
In the “regenerative maximum mode”, when the remaining charge of the battery 13 is low and rapid charging is required, or the in-vehicle power load is large, the regenerative power of the alternator generated power or the wheel drive motor (in the case of an electric vehicle) is regenerated. This is selected when the power is insufficient or when the power generation by the turbine generator (turbo compound) 7 is more efficient than the power generation by the alternator power generation or the regenerative power of the wheel driving motor.

  The “regenerative-free mode” is when the battery 13 is fully charged or close to its charge and cannot be stored even when regenerated, or the in-vehicle power load is generated by the alternator generated power or the regenerative power of the wheel drive motor. If the power generation is sufficient and no additional power is required, or it is more efficient to increase the power generated by the regenerative power of the alternator power generation or wheel drive motor (in the case of an electric vehicle). Or when a failure occurs in the turbine generator (turbo compound) 7.

  The “low fuel consumption mode” does not correspond to the two modes. Considering an increase in engine pumping loss due to an increase in engine back pressure by the turbine generator 7, an optimum power output of the turbine generator 7 is set.

Next, the turbo ECU 17 will be described with reference to FIGS.
As shown in FIG. 1, various signals from the exhaust turbocharger 5 side, as described above, for example, the discharge pressure signal of the compressor 5 b by the pressure sensor 33, the back pressure signal by the back pressure sensor 37, and the exhaust gas temperature by the exhaust temperature sensor 38. Each of the signal and the rotation speed signal of the exhaust turbine 5 a by the rotation speed sensor 35 is input to the sensor signal input unit 43 of the turbo ECU 17.

  The turbo ECU 17 includes a sensor signal input unit 43 and a control calculation unit 45 that are independent from the engine ECU 29. That is, the turbo ECU 17 is not a signal communicated from the engine ECU 29, but has its own rotational speed of the exhaust turbine 5a. A signal that accurately detects (without delay) the outlet pressure of the compressor 5b can be input, and the surge margin until surging of the compressor 5b and the rotational speed margin until overspeed can be grasped. This is because it is possible to obtain without waiting for the communication cycle rather than obtaining it, and it is possible to prevent over-rotation and rushing into surging with accuracy.

  The turbo ECU 17 also includes a margin securing control unit 47 that controls margin securing, a supercharging pressure control unit 49 that controls the supercharging pressure to a target supercharging pressure commanded from the engine ECU 29, and power generation from the engine ECU 29. The power generation mode setting means 31 for setting the power generation mode based on the mode instruction, the power generation amount control means 51 for controlling the power generation amount of the turbine generator 7 according to the setting mode of the power generation mode setting means 31, Back pressure control means 53 for controlling the back pressure.

  FIG. 4 shows the power generation mode setting means 31, the power generation amount control means 51, and the back pressure control means 53. In FIG. 4, the engine ECU 29 receives signals such as the power generation mode instruction, the engine back pressure, the engine speed, the accelerator opening, the target boost pressure, and the boost pressure (feedback value) as described above. Entered.

  When the power generation mode is the regenerative maximum mode, the first wastegate valve 23 and the second wastegate valve 27 are set so that the first wastegate valve 23 is set to the target boost pressure by the boost pressure control means 49. Except for controlling the opening / closing operation, the second wastegate valve 27 is fully closed so that the exhaust gas does not flow through the second bypass passage, but passes through the power generation turbine 7 a of the turbine generator 7. Set to the maximum output state.

  In the non-regenerative mode, the first wastegate valve 23 and the second wastegate valve 27 control the opening / closing operation of the first wastegate valve 23 so that the target boost pressure is achieved by the supercharging pressure control. Except for the above, the second wastegate valve 27 is fully opened, and the exhaust gas is allowed to flow through the second bypass passage 25 to stop the power generation of the turbine generator 7.

In the low fuel consumption mode, a back pressure power generation amount map 55 in which a relationship between the power generation amount of the turbine generator 7 that can maintain low fuel consumption with respect to the back pressure of the engine 3 is preset is used.
This back pressure power generation amount map 55 shows the increase in pumping loss caused by the increase in back pressure generated to rotate the power generation turbine 7a of the turbine generator 7 and the exhaust gas energy obtained by the increase in power generation amount by the turbine generator 7. The power generation amount and back pressure so that the relationship with the recovery amount keeps the engine operating at low fuel consumption, that is, the exhaust gas energy recovery amount by the turbine generator exceeds the fuel consumption deterioration due to the increase in pumping loss. And the relationship is set.
As shown in FIG. 5, for example, the back pressure power generation amount map 55 is a two-dimensional map in which the horizontal axis represents the back pressure and the vertical axis represents the optimum power generation amount, and the setting values calculated in advance by tests or simulation calculations are stored. ing.

The control procedure of the supercharging pressure control and the operation in the low fuel consumption mode is as follows. First, the first wastegate valve 23 and the second wastegate valve 27 are set so that the supercharging pressure control means 49 reaches the target supercharging pressure. The first wastegate valve 23 and the second wastegate valve 27 are opened and closed. Next, the back pressure at the target supercharging pressure, that is, the exhaust gas pressure flowing into the exhaust turbine 5 a of the exhaust turbocharger 5 is detected by the back pressure sensor 37. Next, a power generation amount command value of the turbine generator 7 is obtained for the detected back pressure using the back pressure power generation amount map 55.
Then, the power generation amount feedback value is added to the obtained power generation amount command value by the adder 59, the generator current control value is calculated through the PI controller 61, and the converter 11 is controlled.

On the other hand, the opening degree control of the waste gate valves 23 and 27 is performed by adjusting the back pressure when the target boost pressure is reached, that is, the back pressure when the target boost pressure detected by the back pressure sensor 57 is reached. The opening control of the wastegate valves 23 and 27 is performed so as to be output as a command value and held at this back pressure.
The adder 63 adds the back pressure feedback value to the back pressure command value, calculates the actuator current control value of the wastegate valves 23 and 27 through the PI controller 64, and controls the opening degree.
The opening command value may be controlled for either the first waste gate valve 23 or the second waste gate valve 27, or both may be controlled.

In addition, when setting the optimum power generation amount in the back pressure power generation amount map 55, the power generation amount of the generator 9 can be controlled more accurately by setting the turbine efficiency of the power generation turbine 7a and the generator efficiency of the generator 9 in consideration. It becomes.
That is, as shown in FIG. 5, using the flow characteristic map 65 of the power generation turbine 7a, the turbine efficiency map 67 of the power generation turbine 7a, and the generator efficiency map 69 of the power generator 9, the characteristics of the power generation turbine 7a and the turbine If the back pressure power generation amount map 55 is created reflecting the efficiency and the power generation efficiency, the power generation amount can be controlled with higher accuracy.

  In addition, as another method for executing the fuel efficiency reduction operation of the engine, as described above, a method for creating the back pressure power generation amount map 55 that can be operated in a low fuel efficiency in advance is used. It can be done by the method of

  In this model predictive control, when the controlled object is given by the following state equation (1) of a general nonlinear system, the following evaluation function equation (2) is solved at each time t, and only the value at the time t is obtained. This is a control method used as an actual control input.

  Specifically, as the stage cost term of the evaluation function formula (2), for example, “the difference between the power generated by the turbo compound and the increase in pumping loss” and “the difference between the target supercharging pressure and the actual pressure” are set. Each contribution can be given as a weight for addition. Further, if a surge margin or a rotation speed margin is set as a penalty function in the stage cost term, it can be handled as a constraint condition that a surge or excessive rotation is not substantially caused.

According to the first embodiment described above, the optimization method using the back pressure power generation amount map 55 in which the relationship between the back pressure and the power generation amount capable of maintaining a preset low fuel consumption operation is set, and the model predictive control theory is used. The relationship between the increase in pumping loss caused by the increase in back pressure for rotating the power generation turbine 7a of the turbine generator 7 and the amount of exhaust gas energy recovered due to the increase in the amount of power generated by the turbine generator 7 is This can be achieved by setting the relationship between the power generation amount of the turbine generator 7 and the engine back pressure so that the amount of exhaust gas energy recovered by the generator exceeds the fuel consumption deterioration due to the increase in pumping loss.
As a result, an engine equipped with a turbo compound can be operated with reduced fuel consumption.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.
The second embodiment includes a variable nozzle mechanism 71 that restricts the exhaust gas flow flowing into the moving blades of the exhaust turbine 5a in place of the first wastegate valve 23 of the first embodiment.
That is, this is a case where a VG (Variable Geometry) turbocharger is used. In FIG. 6, the engine ECU 29 and the turbo ECU 17 are not shown.

The variable nozzle mechanism 71 is a mechanism provided in the casing of the exhaust turbocharger 5. For this reason, in the structure in which the first wastegate valve 23 is provided, the first bypass passage 21 needs to be newly piped. However, in the present embodiment, such a pipe is unnecessary and the structure of the turbo compound system is simple. Therefore, the turbo compound system can be downsized. About others, it has the same operation effect as a 1st embodiment.
Instead of providing the variable nozzle mechanism 71 in place of the first wastegate valve 23 of the first embodiment, these may be provided side by side.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG.
In the third embodiment, an electric compressor 81 that pressurizes intake air is provided in the intake passage 4 in addition to the second embodiment, and the intake air is pressurized in two stages. The same components as those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 7, an electric compressor 81 is provided on the downstream side of the intake air flow of the exhaust turbocharger 5 to further pressurize the intake air. The electric compressor 81 includes a motor 83 and an inverter 85, and a control signal from the turbo ECU 17 is input to the inverter 85 to control the supercharging pressure.

The electric compressor 81 becomes a power consumption factor and is added as a power load, and the turbine generator 7 generates a negative impact on the engine that increases pumping loss as a back pressure increasing factor by the power generation turbine 7a instead of generating electric power. Let
However, the electric compressor 81 has a positive effect on the engine 3 by increasing the supercharging pressure to the engine 3 instead of consuming electric power, and contributes to low fuel consumption operation.

Therefore, as control, the power consumption of the electric compressor 81 and the engine output increase are added to the control of the first embodiment.
Specifically, the pumping loss in the first embodiment is the pumping loss and the power consumption of the electric compressor 81, and the power generation amount in the first embodiment is the power generation amount and the engine output increase amount by the electric compressor 81.

  That is, using a map similar to the back pressure power generation amount map 55 of the first embodiment, the back pressure on the horizontal axis is replaced with (back pressure + power consumption of the electric compressor 81), and the optimal power generation amount on the vertical axis is replaced. Using the back pressure power generation amount map 55 ′ in which the relationship of (the power generation amount of the turbine generator 7 + the engine output increase amount by the electric compressor 81) is set, Control is performed in the same manner as in the first embodiment based on the relationship.

  For example, the electric compressor 81 or the variable nozzle mechanism 71 is operated so as to achieve the target supercharging pressure. Thereafter, the power generation amount of the turbine generator 7 at the back pressure in the state where the target supercharging pressure is reached is calculated based on the newly set back pressure power generation amount map 55 ′ so as to be the power generation amount. The variable nozzle mechanism 71 or the second wastegate valve 27 is controlled so as to control the converter 11 of the generator 9 and maintain this back pressure using the back pressure at the target supercharging pressure as a back pressure command value. Either one or both are controlled.

According to the third embodiment, since the electric compressor 81 is added, the intake pressure to the engine can be quickly controlled to the target air pressure as compared with the first and second embodiments. Further, as in the first and second embodiments, since it can be controlled to the target supercharging pressure without increasing the back pressure as compared with the case of only the exhaust turbocharger 5, it has an effect of reducing the pumping loss.
Although the example in which the electric compressor 81 is provided on the downstream side of the intake air flow of the exhaust turbocharger 5 has been described, conversely, it may be provided on the upstream side.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIG.
In the fourth embodiment, instead of the exhaust turbocharger 5 of the first embodiment, only the electric compressor 81 described in the third embodiment is provided.
As shown in FIG. 8, the intake passage 4 is provided with an electric compressor 81, the exhaust passage 19 is provided with a turbo-compound turbine generator 7, and the second bypass passage 25 that bypasses exhaust gas to the power generation turbine 7a A second wastegate valve 27 is provided.

In this way, in the turbo compound system in which the electric compressor 81 and the turbine generator 7 are respectively disposed on the intake passage 4 side and the exhaust passage 19 side, the exhaust gas to the power generation turbine 7a of the turbine generator 7 is bypassed. Back pressure control means for controlling the engine back pressure is configured by the second wastegate valve 27, and power generation amount control means for controlling the power generation amount by the converter 11 connected to the generator 9 of the turbine generator 7 is configured. Therefore, it becomes possible to control the back pressure and the power generation amount with a simple configuration.
Further, the control method is performed in the same manner as in the first embodiment, and the back pressure is controlled only by the second wastegate valve 27, so that it is simplified.

  According to the present invention, the back pressure is controlled in consideration of the trade-off relationship (a trade-off relationship) between the deterioration in fuel consumption due to an increase in pumping loss due to an increase in the back pressure of the engine and the improvement in fuel consumption due to the recovery of exhaust energy by the turbo compound. In addition, since it is possible to reduce the fuel consumption of the engine by controlling the output of the generator, it is effective for application to a control device of a turbo compound system.

1 Turbo Compound System 3 Engine 5 Exhaust Turbocharger (Turbocharger)
7 Turbine generator (electric turbo compound)
9 Generator 11 Converter (Power generation control means)
13 Battery 15 Auxiliary machinery 17 Turbo ECU (Turbo controller)
23 First wastegate valve (back pressure control means)
27 Second Wastegate Valve 29 Engine ECU (Engine Controller)
31 power generation mode setting means 33 pressure sensor 35 rotation speed sensor 37 back pressure sensor 38 exhaust temperature sensor 39 target boost pressure map 41 power generation mode determination means 43 sensor signal input section 45 control calculation section 47 margin securing control means 49 boost pressure control Means 51 Power generation amount control means 53 Back pressure control means 55 Back pressure power generation amount map 65 Flow characteristic map of power generation turbine 67 Turbine efficiency map of power generation turbine 69 Generator efficiency map of generator 71 Variable nozzle mechanism 81 Electric compressor 83 Motor 85 Inverter

Claims (6)

An exhaust turbine driven by exhaust gas from the engine, and an exhaust turbocharger comprising a compressor that compresses intake air and supplies the compressed air to the engine ;
A turbine generator comprising a power generation turbine driven by exhaust gas from the exhaust turbine, and a generator connected to the power generation turbine ;
Power storage means for storing the power generated by the generator;
An engine controller for controlling operation of the engine,
While calculating the target boost pressure based on the engine speed and engine load of the engine,
Based on the target supercharging pressure and the remaining amount of power stored in the power storage means, a regenerative maximum mode in which a regenerative operation is performed with a maximum capacity without limiting the power generated by the turbine generator, and a regeneration that stops power generation by the turbine generator. An engine controller that includes a power generation mode determination means that determines any command power generation mode of a no-power mode, or a low fuel consumption mode that is set when none of the maximum regeneration mode and the no regeneration mode is set;
A turbo controller in which the target boost pressure and the command power generation mode are transmitted from the engine controller at a predetermined communication cycle;
A supercharging pressure control means for controlling a supercharging pressure of the exhaust turbocharger based on an instruction of the target supercharging pressure from the engine controller;
Power generation mode setting means for setting a power generation mode based on an instruction of the power generation mode from the engine controller;
A power generation amount control means for controlling the power generation amount of the turbine generator according to the power generation mode set by the power generation mode setting means; and
Back pressure control means for controlling the variable nozzle mechanism to narrow the first bypass control valve bypassing the exhaust gas to be introduced to the exhaust turbine or gas to be introduced into the exhaust turbine,
A control arithmetic unit having
A sensor signal input unit to which a sensor signal from an exhaust pressure sensor for detecting the pressure of exhaust gas flowing into the exhaust turbine is input;
Including a turbo controller, and
The turbo controller
In the low fuel consumption mode, the engine maintains the low fuel consumption operation based on the relationship between the increase in pumping loss caused by the increase in back pressure for rotating the turbine generator and the amount of exhaust gas energy recovered by the turbine generator. And is configured to control the power generation amount control means and the back pressure control means ,
In the low fuel consumption mode, the supercharging pressure control means controls the supercharging pressure of the exhaust turbocharger to become the target supercharging pressure, and flows into the exhaust turbine in the state where the target supercharging pressure is reached. The power generation amount control means and the back pressure control means are configured to be controlled based on the pressure of the exhaust gas.
A control device for a turbo compound system.   The turbo controller has a back pressure power generation amount map in which a relationship with the power generation amount of the turbine generator capable of maintaining low fuel consumption with respect to the back pressure is set in advance, and based on the back pressure power generation amount map, 2. The turbo compound system control device according to claim 1, wherein the power generation amount control means and the back pressure control means are controlled. The back pressure control means is configured to control the first bypass control valve, and the power generation amount control means is configured to control a converter connected to the turbine generator. Item 4. A turbo compound system control device according to Item 1. Wherein the power generating turbine of the turbine generator to the exhaust downstream side of the exhaust gas turbocharger is disposed, the back pressure control means is arranged to control the variable nozzle mechanism, the power generation amount control means, the turbine generator 2. The turbo compound system control device according to claim 1, wherein the control device is configured to control a converter connected to the machine. The upstream or downstream side of the air supply of the compressor of the exhaust turbocharger, the control apparatus of the turbocompound system according to claim 3 or 4, wherein in that disposed an electric compressor. An electric compressor that compresses intake air into the engine and supplies the compressed air to the engine;
A power generator turbine rotated by exhaust gas from the engine, and a turbine generator comprising a power generator connected to the power generator turbine;
Power storage means for storing the power generated by the generator;
An engine controller for controlling operation of the engine,
While calculating the target boost pressure based on the engine speed and engine load of the engine,
Based on the target supercharging pressure and the remaining amount of power stored in the power storage means, a regenerative maximum mode in which a regenerative operation is performed with a maximum capacity without limiting the power generated by the turbine generator, and a regeneration that stops power generation by the turbine generator. An engine controller that includes a power generation mode determination unit that determines a power generation mode in any of a non-recovery mode, or a low fuel consumption mode that is set when none of the maximum regeneration mode and the no regeneration mode is set;
A turbo controller in which the target boost pressure and the power generation mode are transmitted from the engine controller at a predetermined communication cycle;
A supercharging pressure control means for controlling a supercharging pressure of the electric compressor based on an instruction of the target supercharging pressure from the engine controller;
Power generation mode setting means for setting a power generation mode based on an instruction of the power generation mode from the engine controller;
A power generation amount control means for controlling the power generation amount of the turbine generator according to the power generation mode set by the power generation mode setting means; and
Back pressure control means for controlling a second bypass control valve for bypassing exhaust gas to the power generation turbine;
A control arithmetic unit having
A sensor signal input unit to which a sensor signal from an exhaust pressure sensor for detecting the pressure of the exhaust gas flowing into the power generation turbine is input;
Including a turbo controller, and
The turbo controller
In the low fuel consumption mode, the engine maintains the low fuel consumption operation based on the relationship between the increase in pumping loss caused by the increase in back pressure for rotating the turbine generator and the amount of exhaust gas energy recovered by the turbine generator. And is configured to control the power generation amount control means and the back pressure control means ,
In the low fuel consumption mode, the supercharging pressure control means controls the supercharging pressure of the electric compressor to be the target supercharging pressure, and based on the exhaust gas pressure in the state where the target supercharging pressure is reached. A turbo compound system control device configured to control the power generation amount control means and the back pressure control means .

Images